Contamination of Pork Carcasses during Slaughter, Fabrication, and Chilled Storage

In an attempt to determine points of greatest pathogenic contamination of pork, the prevalence of five pathogens was determined on pork carcasses at specific points during slaughter, fabrication, and refrigerated storage. Pork carcass and loin surfaces were swabbed at three hog slaughtering plants. Carcasses were swabbed after singeing, after the final wash of the slaughter process, and after 24 h of chilled storage. Boneless loins were swabbed after trimming and deboning, but before packaging. Also, vacuum-packaged loins were sampled after 36 days of storage at 2°C. Staphylococcus aureus , Salmonella spp., and Listeria monocytogenes were the most prevalent. S. aureus isolates showed a significant linear increase (P = 0.0399) from slaughter to fabrication processes, with the highest numbers detected after 24 h of refrigerated storage. Trimming fat from surfaces of pork loins reduced the number of initial S. aureus counts, but there was no further reduction after 36 days of refrigerated storage. Salmonella were isolated primarily from pork before fabrication and refrigerated storage. A continuous reduction in the numbers of Salmonella isolates was detected from the point of singeing to the point of fabrication. No Salmonella were isolated from vacuum-packaged pork stored for 36 days at 2°C. The relatively higher prevalence of the psychrotrophic pathogenic bacteria L. monocytogenes and Yersinia enterocolitica in vacuum-packaged pork loins after 36 days of storage at 2°C indicates the need for proper cooking and handling of meats prior to human consumption.